The study found that 39.4 percent of parents incorrectly measured the dose they intended, and ultimately 41.1 percent made an error in measuring what their doctor had prescribed. Part of the reason why parents may be confused regarding how to dose prescribed medications accurately is that a range of units of measurement, like milliliters, teaspoons and tablespoons, may be used interchangeably to describe their child's dose as part of counseling by their doctor or pharmacist, or when the dose is shown on their prescription or medication bottle label.

Due to concerns about these issues, use of the milliliter as the single standard unit of measurement for pediatric liquid medications has been suggested as a strategy to reduce medication errors by organizations like the American Academy of Pediatrics (AAP), Centers for Disease Control (CDC), and the Institute for Safe Medication Practices.

In this study, compared to parents who used milliliter-only units, parents who used teaspoon or tablespoon units to describe their child's dose of liquid medicine had twice the odds of making a mistake in measuring the intended dose. Parents who described their dose using teaspoons or tablespoons were more likely to use a kitchen spoon to dose, rather than a standardized instrument like an oral syringe, dropper, or cup. Even those who used standardized instruments were still more likely to make a dosing error if they reported their child's dose using teaspoon or tablespoon units. Parent mix up of terms like milliliter, teaspoon and tablespoon contribute to more than 10,000 poison center calls each year.

Study authors conclude that adopting a milliliter-only unit of measurement can reduce confusion and decrease medication errors, especially for parents with low health literacy or limited English proficiency.